Mucorales

The primary symptom of infection by Mucorales fungi is the appearance of dense, fluffy mycelium that resembles white or grey cotton wool.

Affected plant tissues typically undergo rapid softening, becoming watery and losing their structural integrity within a short period.

As the fungi reproduce, the mycelial mat turns dark grey, brownish, or black due to the formation of numerous spore-bearing sporangia.

A distinct, unpleasant, or fermentation-like odor is often associated with the decomposition of tissues caused by these opportunistic pathogens.

In advanced stages of infection, the entire organ may collapse, turning into a slimy, disorganized mass, making it completely inedible and non-marketable.

The disease is caused by fungi belonging to the Mucorales order within the Mucoromycotina subphylum.

These organisms are typically saprotrophs that thrive on decaying organic matter but can become aggressive pathogens on damaged or stressed crops.

They are characterized by coenocytic mycelium, which lacks septa, allowing for rapid nutrient transport and aggressive growth colonization.

Reproduction occurs via asexual spores produced in sporangia, which are dispersed easily by air currents and water splashes.

Their high enzymatic activity enables them to rapidly degrade pectins and other cell wall components, leading to tissue liquefaction.

High relative humidity, typically exceeding 80-85%, is the most critical environmental factor promoting the development of these fungi.

The optimal temperature range for mycelial growth and rapid spore production is between 20 and 25 degrees Celsius.

Poor ventilation in storage facilities often leads to localized pockets of high humidity and stagnant air, creating perfect conditions for an outbreak.

Mechanical damage to the skin of fruits, vegetables, or tubers provides easy entry points for spores to germinate and invade healthy tissues.

Large quantities of decaying plant debris left in fields or storage areas act as a major inoculum reservoir for subsequent infections.

Mucorales fungi cause significant post-harvest losses, potentially destroying entire batches of fruits and vegetables in storage.

A wide range of crops is susceptible, including tomatoes, strawberries, sweet potatoes, carrots, and various cereal grains.

The infection spreads rapidly from contact between infected and healthy produce, which can result in total crop failure in warehouse settings.

Besides economic losses, contaminated produce may contain mycotoxins, making the crop unsafe for human consumption or animal feed.

The need for intensive sorting and waste disposal increases labor costs and negatively impacts the overall profitability of agricultural operations.

Maintaining a strict temperature and humidity control strategy in storage facilities is the most effective way to prevent fungal growth.

Effective ventilation and air circulation systems should be implemented to prevent the formation of condensation on produce surfaces.

Sanitation of storage areas, shipping containers, and grading equipment using appropriate disinfectants is vital to reduce pathogen load.

Minimizing mechanical injury during harvest and transportation is essential to maintain the natural barrier of the plant against infection.

• Regular removal of diseased plant parts from the field.
• Proper crop rotation to reduce soil-borne inoculum.
• Using fungicide treatments during seed preparation or pre-harvest if necessary.